1. 18th Annual Primary Care and Cardiovascular Symposium
Acute Chest Pain Evaluation in the ED
18th Annual Primary Care and Cardiovascular Symposium

2. Acute Coronary Syndrome
In the United States we see > 8 million patients per year with chest pain.
1.6 million get hospitalized
~ 15% low risk, ~ 15% high risk
Intermediate risk comprises ~ 70 % and have a risk of death or MI of % at days
Patients without enzyme elevation still have a risk ~ 5% of death or MI at 30 days.
AMI is present around 6% with a normal or non-diagnostic ECG.

3. Malpractice
2 - 8% of patients with AMI are sent home with an associated risk of death ~ 10% (1/5 of all malpractice dollars)
In one insurance industry–based study, the physician group most likely to be sued for missed myocardial infarction (MI) was family practitioners (32%), followed by general internists (22%) and ED physicians (15%).
To meet this challenge, an increasing array of diagnostic modalities have been investigated during the past 2 decades.

4. Patient’s Understanding
“Am I having a heart attack?”

5. History
One of the most predictive of ACS (substernal 1, provoked by exertion or rest2 and relieved by NTG3)
At least an intermediate probability if age > 30
Atypical (lacks 1 of 3)
Intermediate if male > 30 or woman > 50
Cardiac Risk Factors
Predict lifetime risk but not acute episode

6. ECG Mainstay in Screening Only diagnostic in a minority of cases
Ischemic changes are apparent at the time of presentation in only 20% to 30% of patients who have an acute MI
Conversely, 5% to 10% of patients with MI have normal findings on ECG at presentation.
If abnormal, offer prognostic information
With Pain
Can diagnose only 35% of the time
Physician + ECG
Increases diagnostic ability to only 52%

7. Cardiac Markers
Even minor elevation in Troponin places the patient at increased risk for a coronary event

8. SPECT Imaging Single Photon Emission Computed Tomography
Injected with non-diagnostic ECG and active chest pain
Detects 96% of CAD
Subsequent cardiac events predicts 92%
Negative scan
< 2% in hospital event
Safely discharged from Emergency Department

9. SPECT Scan

10. Nuclear Imaging
Before Intervention
After Intervention

11. Echocardiography User Dependent (Chest pain & non-diagnostic ECG)
Sensitivity of 88%
Specificity 78%
Sensitivity Varies with MI size
100% sensitive with Ant MI with > 18% involvement of LV mass
With only 1-6 % of LV mass
Hypokinesis occurs in 30%
Dyskinesis in 10% (only > 20% of transmural thickness)
Cannot effectively distinguish acute ischemia from infarction: limiting its role in patients with chest pain and history of coronary artery disease

12. Echocardiography Useful with ongoing atypical chest pain to view
Valvular disease
Dissections
Ventricular or aortic aneurysms

13. Stress Testing Results in decreased exercise capacity (METs)
Major hemodynamic consequence of CAD is decreased cardiac output
Results in decreased exercise capacity (METs)
While exercising the probability and severity of CAD is related to
ST depression or
ST downslope
Sensitivity 67%
Specificity 72%
IF 1 mm ST depression
50-70% single vessel disease
80-90% three vessel disease
To improve sensitivity routine stress
is coupled with echo or nuclear

14. ST Depression
ECG During Stress

16. ECBCT The presence of calcium suggests coronary plaque
Quantity of calcium correlates with histologic plaque mass (Agatston score or Shemesh visual scoring system)
Serve as a marker for severity but does not directly localize coronary stenosis
Sensitivity % Specificity 60-70%

17. Absence of Coronary CalcificationPA AO
LMCA

18. Moderate Coronary CalcificationPA AO
LAD

19. Severe Coronary Calcification
The relationship between
CAC and biologically “unstable” coronary artery plaque prone to rupture is still not totally understood.
No CAC or CACS 0 has a less < 1% risk

20. Coronary CT Angiography
Noninvasive imaging modality which can be used to evaluate the anatomy of the coronary arteries. Need 64 slice CT scanners
Unlike coronary artery calcium scoring, which utilizes noncontrast CT to assess atherosclerotic disease burden, CCTA allows direct visualization of the coronary artery wall and lumen with the administration of intravenous contrast.

21. Coronary CT Angiography
The degree of coronary luminal stenosis can be reliably estimated, as can the presence or absence of both calcified and non-calcified plaques.
When compared to invasive quantitative coronary angiography, newer-generation CT scanners have been found to have sensitivities and specificities of over 90%, and negative predictive values of up to 100% for the exclusion of obstructive coronary artery disease (CAD) for both native arteries as well as bypass grafts.

22. CTA
Use in asymptomatic patients with traditional risk factors is controversial, and has not been widely recommended.
The use of CCTA in high risk patients with chest pain is generally not recommended, as these patients often require cardiac catheterization.
CCTA involves a significant radiation exposure, on the order of mSv (chest x-ray is about 0.05 mSv; technetium stress test is about 10 – 12 mSv; thallium stress test is about mSv).

24. Cardiac MRI

25. MRI Limited Use Currently Awaiting faster scanners
Have to maintain slower heart rate

26. Angiography TIMI IIIb (unstable angina or non Q MI)
No significant disease in 19%
One vessel 38 %
Two vessel in 29%
Three vessel in 15%
Left main 4%
Recommended for patients with the diagnosis of ACS & pain > 1 hour after initial aggressive medical therapy

27. Conclusion Each of these modalities have strengths & weakness
The cost of caring for patients admitted to the hospital to r/o ACS is ~ 13 billion dollars/year
ED’s now have protocols that take advantage of our current knowledge and research
By doing this patients can be safely and expeditiously re-stratified into low, intermediate and high risk groups.

28. Disclosures
None

29. Any Questions ?